The invention relates to the field of printer cost estimation systems. More particularly, the invention relates to a toner usage estimation system to determine the cost of consumable materials for printed documents.
Printer manufacturers generally estimate printed page cost based on a rough estimate of 5% toner coverage across a page. While this estimate can provide a comparison of the relative cost of printing an image between different printers, the actual toner page coverage between different printed pages can vary significantly from printer manufacturer""s estimates. Therefore, the actual cost per printed page can vary significantly for different print jobs.
The number of toners used in print engines typically varies from one toner (monochrome printing) to four toners (cyan, magenta, yellow, and black)(commonly referred to as CMYK). Some specialized printing processes may use more than four toners, such as an enhanced four color CMYK process that includes the additional application of one or more spot colors.
The cost of consumables in printing processes can be significant, particularly for many color printers that use advanced toners or application techniques, such as for ink jet, thermal wax transfer or dye-sublimation printers.
An exact toner bit map of a page image is generally never held in any memory. With current analog screening techniques, a contone (CMYK)(color) or K (monochrome) image bit map is submitted, as a data stream, to a halftone screening circuit within a printer controller. The printer controller then generates commands to release toner upon a substrate to produce a printed image, based upon the bit map of the page image. The toner is deposited onto the substrate, in a proportion relative to the specified percentage of C, M, Y and K present in the data stream.
M. Farrell, Method of Estimating Cost of Printing Materials Used to Print a Job on a Printing Apparatus, U.S. Pat. No. 5,383,129 (Jan. 17, 1995) discloses a method of estimating the cost of printing materials used to print a job on a printing apparatus, which includes the steps of storing billing rates reflecting the cost of printing materials to be used in printing the job, selecting a first quantity of printing materials to be used in printing the job, and prior to printing the job, calculating as a function of the first selected quantity of printing materials and one of the stored billing rates, a first printing materials cost of the job. While Farrell discloses print cost estimation methods based on a number of stored billing rates and materials costs, he fails to disclose a system for estimating the cost of toner for each job based upon the image file bit map.
Some computer and printer systems provide reduced resolution (thumbnail) images of ripped jobs as previews of images to be printed. While thumbnail images are extremely condensed bit map files of original image files, they provide a reasonably accurate compressed representation of image files.
It would be advantageous to provide a method and apparatus to estimate toner usage for print jobs based on the image data from each job. It would also be advantageous to provide a method to estimate toner usage for print jobs based on thumbnail image bit maps.
While the disclosed prior art system and methodology provides a basic printing cost estimation system, it fails to provide a toner usage estimation system that bases estimations on the image or document files to be printed. The development of such a toner usage estimation system would constitute a major technological advance.
A toner usage estimation system is provided, in which an image file is analyzed to determine the relative usage of one or more toners used to define an image on a substrate. The image file is analyzed as a basis for estimating the cost of processing a particular print job. In one embodiment, a pixel-coverage counter is added in the hardware path of a printer to count pixel coverage mapping, which allows the consumable usage of toner to be determined. In another embodiment, a software approximation on the coverage of toner is determined, based on the use of a reduced resolution thumbnail of an image.